What is Turbo-lag: Explained

Manufacturers have been using turbochargers in their diesel engines and recently some carmaker like Mahindra and Hyundai have begun using them in their petrol engines. One reason to use turbochargers is the stricter regulations which have caused manufacturers to downsize their engines. So, to increase the power and efficiency, they are using turbochargers on their downsized engines.

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One major issue that comes with turbocharging is the turbo-lag. Some people hate turbocharged engines because of this but some people do love it. That is because of the kick-in- the-pants feel that comes with the torque surge. To understand what turbo-lag we need to understand some basics of a turbocharger.

What does a turbocharger do?

There are two ways to increase the power output of an engine. Either you can increase the amount of air in the engine or increase the amount of fuel. Increasing the amount of fuel will result in an increase in the consumption of fuel which will decrease fuel efficiency. However, we can increase the amount of air which is more beneficial for the engines. This is where the turbocharger comes into play. Turbocharger forces more air into the engine which makes the bigger explosion in the cylinder. Thus, increasing the power and torque output.

How does a turbocharger work?

A turbocharger runs with the help of exhaust gases and it consists of a turbine inside. The exhaust gases are divided into two paths. One of them goes to the turbocharger and the other one goes to the exhaust system. These exhaust gases are captured by one end of the turbo and are used to spin it. This exhaust turbine is connected to an intake turbine. So, when the exhaust gases spin the exhaust turbine, the intake turbine automatically spins. As the intake turbine spins, it pulls in more air for the engine.

What is turbo-lag?

Turbo-lag is the time you face between stepping on the gas and feeling the torque surge. Some engines have almost zero turbo lag, some have a lot of it. But there isn’t an engine out there that can have an immediate hit of boost below its boost threshold RPM. It’s just not possible because it will always take some time for the turbocharger to reach its maximum efficiency.

What are the causes of turbo-lag?

Turbo-lag happens because the turbines inside the turbos need some time to spool. When the engine revs are less, there are not enough exhaust gases to spin up the turbo. But once the engine revs increase and there are enough exhaust gases produced to spin up the turbo and then you get the torque surge

How to avoid turbo-lag?

There is only one way to avoid turbo-lag and that is to keep your car in the power-band of your rev-range. The power-band is that part of the rev-range when your turbocharger is spooled up and is producing maximum power. Obviously, you cannot avoid the turbo-lag in the first gear but in other gears, you can. You would need to down-shift or keep your car in a lower gear so that your engine revs increase. This will make sure that your turbocharger is spinning at its maximum. However, also remember that more revs mean that you will be consuming more fuel and that will decrease your fuel efficiency.

There is no denying the fact that downsizing is the future because of the stricter emission norms. Engines with big displacements get heavy taxes from the government too and less fuel efficiency. Because of this manufacturer are trying to use force induction on their small-displacement engines and by far they have not disappointed. Hyundai Venue, Kia Seltos, Mahindra XUV300, Volkswagen Polo TSI and even the Hyundai Aura which is a compact-sedan have gotten positive reviews from the automotive journalists. So, we can say that the future of the automotive industry should be pretty interesting for people who like driving cars.